PURPOSE: To position a recording means such as a recording pen automatically at a ruled line behind an adjacent ruled line on the basis of position information on the recording means about ruled lines on recording paper when the recording paper and recording means stop changing in relative position.

CONSTITUTION: The recording paper 10 is displaced by a pulse motor 12 in a lateral-axis direction and the recording pen 14 is driven for displacement in a longitudinal-axis direction. Ruled lines 16 are printed previously on the recording paper 10 and the pulse motor 12 is controlled under the command of a CPU18. Outputs of an analyzer, etc., are fetched in an RAM24 through input/output interfaces (I/O). Data on various condition setting are inputted on a keyboard 26. Data and control instructions are transferred among the respective I/Os, RAMs, ROMs, and the CPU through a bus line 30. Further, the recording pen is positioned at the ruled line behind the adjacent ruled line, so recording results are discriminated more easily.